Response of Slenderleaf (crotalaria brevidens benth) to inorganic nitrogen application

Abstract

Slenderleaf is one of African Leafy Vegetables that has been grown and consumed in Kenya for a long time, its young leaves and shoots are used as a cooked vegetable. Slenderleaf acts as an agent to promote suicidal germination of Striga, a parasitic plant that is a major problem weed for maize and millet growers. One of the major constraints in its production has been poor quality seed and lack of technical packages for optimal production. Although slenderleaf has high germination percentage that occurs within 5 days, there is hardly any information on nitrogen nutrition and the longevity of slenderleaf seed and factors affecting them. The objectives of this study therefore were: to investigate the effect of nitrogen rates on growth, leaf and seed yield of Crotalaria brevidens and to study the effect of storage period on germinability of Crotalaria brevidens. Seeds of slenderleaf were obtained from Maseno University, Botanic garden and subjected to germination tests and then planted in the field in a well prepared seed bed at Maseno University experimental plots at a spacing of 30x30cm. The design of the experiment was RCBD with 6 treatments and three replications and each plot measured 1.5 x 2m. The treatments included six nitrogen rates (0, 10, 20, 40, 80 and 100 kg N per hectare). Measurements on plant height, number of leaves, number of branches and number of flowering plants were taken regularly. Seeds were harvested, processed and seed yield determined and the seeds from the various treatments were kept in airtight containers and stored at room temperature in September 2003. Germination tests were carried out by placing 50 seeds from each treatment randomly selected into a Petri-dish lined with a wet filter paper every 6 months commencing September 2003 for a period of two years and germination percentage determined. Results indicated that nitrogen rates did no t have a significant (p>0.05) effect on growth, leaf and seed yields. Seed yields varied from 0.42 to 0.59 kg/m2. Nitrogen rates had no significant (p>0.05) effect on the germination percentage in the period of storage. In September 2003, the mean germination percentage was 96.8% while in September 2005 it was 95%. The findings of this study indicate that Nitrogen application may not always be necessary for growing slenderleaf and seed can be stored for 2 years without loss of germinability and viability.